1 files changed, 52 insertions, 8 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 9cd5a717ede..dd76765310c 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1504,6 +1504,12 @@ static void shadow_walk_init(struct kvm_shadow_walk_iterator *iterator,
         iterator->addr = addr;
         iterator->shadow_addr = vcpu->arch.mmu.root_hpa;
         iterator->level = vcpu->arch.mmu.shadow_root_level;
+
+        if (iterator->level == PT64_ROOT_LEVEL &&
+            vcpu->arch.mmu.root_level < PT64_ROOT_LEVEL &&
+            !vcpu->arch.mmu.direct_map)
+                --iterator->level;
+
         if (iterator->level == PT32E_ROOT_LEVEL) {
                 iterator->shadow_addr
                         = vcpu->arch.mmu.pae_root[(addr >> 30) & 3];
@@ -2314,7 +2320,9 @@ static void mmu_free_roots(struct kvm_vcpu *vcpu)
         if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
                 return;
         spin_lock(&vcpu->kvm->mmu_lock);
-        if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
+        if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL &&
+            (vcpu->arch.mmu.root_level == PT64_ROOT_LEVEL ||
+             vcpu->arch.mmu.direct_map)) {
                 hpa_t root = vcpu->arch.mmu.root_hpa;
 
                 sp = page_header(root);
@@ -2394,10 +2402,10 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
 
 static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
 {
-        int i;
-        gfn_t root_gfn;
         struct kvm_mmu_page *sp;
-        u64 pdptr;
+        u64 pdptr, pm_mask;
+        gfn_t root_gfn;
+        int i;
 
         root_gfn = vcpu->arch.mmu.get_cr3(vcpu) >> PAGE_SHIFT;
 
@@ -2426,8 +2434,13 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
 
         /*
          * We shadow a 32 bit page table. This may be a legacy 2-level
-         * or a PAE 3-level page table.
+         * or a PAE 3-level page table. In either case we need to be aware that
+         * the shadow page table may be a PAE or a long mode page table.
          */
+        pm_mask = PT_PRESENT_MASK;
+        if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL)
+                pm_mask |= PT_ACCESSED_MASK | PT_WRITABLE_MASK | PT_USER_MASK;
+
         for (i = 0; i < 4; ++i) {
                 hpa_t root = vcpu->arch.mmu.pae_root[i];
 
@@ -2451,9 +2464,35 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
                 ++sp->root_count;
                 spin_unlock(&vcpu->kvm->mmu_lock);
 
-                vcpu->arch.mmu.pae_root[i] = root | PT_PRESENT_MASK;
+                vcpu->arch.mmu.pae_root[i] = root | pm_mask;
+                vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
         }
-        vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
+
+        /*
+         * If we shadow a 32 bit page table with a long mode page
+         * table we enter this path.
+         */
+        if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
+                if (vcpu->arch.mmu.lm_root == NULL) {
+                        /*
+                         * The additional page necessary for this is only
+                         * allocated on demand.
+                         */
+
+                        u64 *lm_root;
+
+                        lm_root = (void*)get_zeroed_page(GFP_KERNEL);
+                        if (lm_root == NULL)
+                                return 1;
+
+                        lm_root[0] = __pa(vcpu->arch.mmu.pae_root) | pm_mask;
+
+                        vcpu->arch.mmu.lm_root = lm_root;
+                }
+
+                vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.lm_root);
+        }
+
         return 0;
 }
 
@@ -2470,9 +2509,12 @@ static void mmu_sync_roots(struct kvm_vcpu *vcpu)
         int i;
         struct kvm_mmu_page *sp;
 
+        if (vcpu->arch.mmu.direct_map)
+                return;
+
         if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
                 return;
-        if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
+        if (vcpu->arch.mmu.root_level == PT64_ROOT_LEVEL) {
                 hpa_t root = vcpu->arch.mmu.root_hpa;
                 sp = page_header(root);
                 mmu_sync_children(vcpu, sp);
@@ -3253,6 +3295,8 @@ EXPORT_SYMBOL_GPL(kvm_disable_tdp);
 static void free_mmu_pages(struct kvm_vcpu *vcpu)
 {
         free_page((unsigned long)vcpu->arch.mmu.pae_root);
+        if (vcpu->arch.mmu.lm_root != NULL)
+                free_page((unsigned long)vcpu->arch.mmu.lm_root);
 }
 
 static int alloc_mmu_pages(struct kvm_vcpu *vcpu)